Lactulose as a food ingredient

Lactulose is a synthetic ketose disaccharide that can be obtained from lactose by different methods of synthesis. Chemical methods are based on the isomerization of lactose in the presence of basic catalysts and enzymatic methods using lactose as a galactose donor and fructose as an acceptor. The prebiotic properties of lactulose have been known for more than 50 years and numerous studies have confirmed several health benefits of lactulose as a food ingredient, including selective stimulation of intestinal flora, laxative effect and improvement of calcium absorption. Its use in fermented milk manufacture may reduce the incubation period and favour the growth of bifidobacteria. The synthesis of lactulose‐derived oligosaccharides may provide a new group of prebiotics with properties complementary to those of native lactulose. Copyright © 2009 Society of Chemical Industry     

Resistant starch as functional ingredient: A review

Dietary starches are important sources of energy for many human societies and it is clear that they can also make quite specific contributions to health. Resistant starch has received much attention for both its potential health benefits (similar to soluble fibre) and functional properties. Resistant starch positively influences the functioning of the digestive tract, microbial flora, the blood cholesterol level, the glycemic index and assists in the control of diabetes. Apart from the potential health benefits of resistant starch, another positive advantage is its lower impact on the sensory properties of food compared with traditional sources of fibre, as whole grains, fruits or bran. Among its desirable physicochemical properties are its swelling capacity, viscosity, gel formation and water-binding capacity, which make it useful in a variety of foods. In this review, we discuss different types of resistant starch, food sources, and potential health benefits and food applications of resistant starch.     

Characterisation of peach dietary fibre concentrate as a food ingredient

Insoluble and soluble dietary fibre (DF) fractions of peach DF concentrate, obtained by an enzymatic-chemical method, were analysed for neutral sugars, uronic acids and Klason lignin. Proximate composition, energy value, colour and water- and oil-holding capacities were also determined. Total DF constituted 31–36% dry matter (DM) of the concentrate and insoluble DF was its major fraction (20–24% DM). The high proportion of soluble fraction (11–12% DM) in the peach DF concentrate, in comparison with cereal brans, was noticeable. Insoluble and total dietary fibre contents significantly decreased throughout the harvest time of the original fresh fruit. Results suggested that peach DF concentrate may be not only an excellent DF source but an ingredient in the food industry because it showed a high affinity for water (9.12–12.09 g water/g fibre) and low energy (3.723–3.494 kcal/g). However, the use of this material could affect the colour and pH of the final product.     

叶黄素的生物学作用及制剂研究进展

目的：为提升淀粉在载药领域的应用,旨在制备出纳米级疏水改性淀粉,研究其对疏水性药物的负载效果。方法：以木薯淀粉为原料,采用沉降法制备了纳米淀粉（Nanometer Starch,SNPs）,并以脂肪酶为催化剂,在两相体系对SNPs催化改性,合成了不同取代度（Degree of Substitution,DS）的松香酯纳米淀粉（Rosin Ester Nanometer Starch,RENPS）,考察了SNPs和RENPS在不同条件下对叶黄素的吸附效果。结果：酯化改性未对SNPs形貌产生显著影响,SNPs尺寸分布在250～800 nm,主峰为480 nm,RENPS尺寸分布在100～800 nm,DS的增加,使主峰向左移动;DS与RENPS的疏水性呈现正相关,RENPS的接触角可达93.32°±1.15°,SNPs的接触角仅为51.69°±2.15°。随着DS的增加,RENPS对叶黄素吸附达到平衡的时间逐渐减小,但吸附量逐渐增加。SNPs对叶黄素吸附为一级动力学,RENPS对叶黄素吸附为二级动力学。结论：本研究确定了RENPS的一种疏水改性方法,并且改性后的RENPS对疏水性药物的负载能力得到显著提升。     

健康食品配料——低聚异麦芽糖

低聚异麦芽糖又称分歧低聚糖,以淀粉为原料采用酶工程技术生产,是功能性低聚糖中产量最大、应用最广泛的一种健康食品配料。低聚异麦芽糖于80年代在日本成功开发,1990年产量达8,000吨,1995年产量为11,000吨,至1997年已达15,000多吨。由于低聚异麦芽糖具有显著的生理功效,且价格极具市场竞争力,发展速度较快,年平均增长率超过10％。     

Sensory and rheological properties of transgenically and chemically modified starch ingredients as evaluated in a food product model

Starches derived from five genetically modified potato lines, two chemically modified potato starches and two native starches from potato and maize were subjected to physical and chemical analyses and their functionality evaluated in a milk-based food product model. The transgenic starches were specifically modified with respect to amylopectin chain length and phosphorous content by suppression of the starch branching enzyme and overexpression of glycogen branching enzyme. Transgenic starches with long amylopectin chains and high phosphorous content had increased gelatinisation temperatures, produced gels with a higher tendency to retrograde and a low freeze/thaw stability as compared to starches with shorter amylopectin chains and lower phosphorous content. The textural properties of the food product model prepared from genetically and chemically modified starches were characterised by sensory and rheological analyses. To clearly visualise the effects of the modifications, data was evaluated by radar plots and multiple regression analysis (chemometrics). Genetically modified potato starches with longer amylopectin chains and increased phosphorous content gave a more gelled and a shorter texture as compared to starches with shorter amylopectin chains and decreased phosphorous content. Acetylated and hydroxypropylated potato starches gave sticky and stringy textures. Correlations between rheology parameters and sensory parameters were found. The sensory parameter stringy/long could be predicted from the rheological data.     

Analysis of co-crystallized free phytosterols with triacylglycerols as a functional food ingredient

This research focuses on the analysis of mixtures of free phytosterols (FPSs) with fully hydrogenated soybean oil (FHSO):soybean oil (SO) mixtures as a potential zero-trans substitute for various types of shortenings. Oil binding capacity as well as the thermal, rheological and structural properties of FHSO:SO blends containing 0, 20 and 25 wt.% β-sitosterol or stigmasterol were investigated in this study. Differential interference contrast (DIC) microscopy and wide angle X-ray diffraction (WAXRD) revealed that co-crystallization of FPSs with FHSO:SO blends occurred. Polymorphic forms were characterized as a mixture of β′ and β for all samples. The addition of FPSs decreased oil loss (OL) of FHSO:SO samples. Melting profiles of the prepared FPS–TAG (triacylglycerol) blends were extended to higher temperatures compared to a commercial shortening. Rheological properties were comparable to those of commercial puff pastry shortening suggesting that FPS–TAG blends may be acceptable for bakery applications. FPSs co-crystallized with FHSO and SO may be a suitable trans-fat free substitute for a number of types of shortening, including puff pastry shortening. The manufacturing of co-crystallized /FPS-TAG matrices will possibly bring large economic benefits as their functionalization can potentially be achieved by using existing simple shear processing.     

Nutritional characterization of tomato fiber as a useful ingredient for food industry

Tomato by-product consists of peels and seeds, presenting peel high fiber content. In this work, “tomato fiber” (TF) samples, obtained from tomato peels (after tomato processing) by a patented process, were characterized in terms of fiber and macronutrients (proteins, ash, total available carbohydrates and soluble sugars). From our results, TF is mainly composed by carbohydrates, with an average value of 80% of total dietary fiber (much higher than other vegetable by-products), being insoluble fiber the major component. The results obtained in this study reveal the high interest of TF as a food ingredient to be used as a valuable ingredient of new functional foods, enhancing insoluble fiber intake in the population.Industrial RelevanceThe use of tomato by-product reduces costs and justifies new investments in equipment, providing a correct solution for the pollution problem connected with tomato processing. The results obtained in this study reveal the high interest of TF as a food ingredient to be used as a valuable ingredient of new functional foods, enhancing insoluble fiber intake in the population. According to the Regulation 1924/2006, the product TF characterized in this study can be considered under the denomination of “Source of Fiber” (more than 3 g/100 g), and for that reason food products containing the above mentioned fiber in quantities equal or superior to 3.9%, could also include the same declaration of nutritional properties in their labeling.     

魔芋低聚糖作为新食品原料的应用研究

魔芋多糖是魔芋的主要成分,魔芋低聚糖是魔芋多糖经过酶、酸、辐照等多种方法降解得到的寡糖。魔芋低聚糖作为新食品原料在食品及保健食品中有着广阔的应用前景。与魔芋多糖相比,魔芋低聚糖具有优良的性能,可用于改善食品品质,保鲜食品,同时也适用于多种低脂食品的加工和制作,满足各类人群的需求,有利于人体健康。另外,魔芋低聚糖作为功能因子,对机体有多方面的保健功效,有望用于保健食品行业,来改善人体肠道菌群,增强免疫力,调节血糖、血脂等。总之,魔芋低聚糖是一种理想的食品原料或者食品添加剂。本文从魔芋低聚糖的制备,在食品及保健食品中的应用等方面对魔芋低聚糖进行了综述。     

Functional performance of a resistant starch ingredient modified using a microfluidiser

The effects of microfluidisation on a suspension of a resistant starch ingredient (high-amylose corn starch with 58% resistant starch) in water, that was previously heated (121 °C/60 min) and subjected to shearing using a Silverson Mixer, was examined. Heating and shearing starch suspensions, with or without a subsequent microfluidisation treatment, caused a reduction in the resistant starch content to ~ 30%. There was a decrease in the estimated molecular weight of the starch due to scission of the starch molecules following heating and shearing of the starch suspension and a further reduction with the subsequent microfluidisation of this suspension. Heating and shearing of the starch suspension increased its viscosity. The combined use of heat treatment, shearing and microfluidisation further significantly increased the viscosity of starch suspensions, depending on the pressure used during microfluidisation and the number of passes. The performance of the treated starch suspensions in stirred yoghurts was investigated to assess their ability to contribute to the physical properties in this application. Substitution of 3% milk solids in yoghurts (12% total solids) with heated, sheared and microfluidised starch suspensions significantly (p < 0.05) increased the viscosity and decreased syneresis of yoghurts but the incorporation of starch that had only been heated and sheared without microfluidisation did not. The results indicate that a treatment process for resistant starch which incorporates microfluidisation could potentially produce a new functional resistant starch ingredient with increased viscosity and water-holding properties.Industrial relevanceResistant starches have an important role in human health and are sought-after ingredients for functional foods, i.e. foods with benefits beyond normal nutrition. The incorporation of resistant starches into processed foods is often a challenge as the added starch can detract from the texture of the food. A limitation is the inability of most resistant starches to build viscosity. Our research has shown that it is possible to make a physically functional resistant starch ingredient by the application of physical processes to a starch suspension. This chemical-free process enables the production of a differentiated resistant starch ingredient that has the ability to build viscosity and contribute to the texture of a finished food product. It provides a potential solution for the incorporation of resistant starch into processed food products.     

Shrimp processing residue as an alternative ingredient for new product development

Shrimp residues were dried (65 °C), grounded, and posteriorly used as an ingredient to the production of ‘spiced shrimp flour’ and ‘shrimp flavoured biscuits’. Both products were packed in modified atmosphere (100% N₂) and stored for 180 days (25 °C) for shelf life evaluation. The centesimal composition, physicochemical, microbiological and sensory analyses were carried out in triplicate. The microbiological analysis (residue and shrimp flour) was within the limits of the legislation, confirming the hygienic–sanitary care during processing. The protein content was the most outstanding (40.13% for the spiced shrimp flour and 20.52% for the shrimp flavoured biscuits). The microbiological evaluation for the ‘spiced shrimp flour’ and ‘shrimp flavoured biscuits’ was below the legal limit, and both products were accepted by sensory analysis. The shelf life evaluation demonstrated stability for 6 months. Thus, we concluded that the Litopenaeus vannamei shrimp residue is a promising ingredient in the food industry.     

Characterisation of reused osmotic solution as ingredient in new product formulation

Osmotic dehydration (OD) with sugar solutions has been used in fruit preservation but part of the process's economic viability depends on the possibility of reusing the osmotic solution (OS) in successive dehydration cycles. Despite the increase in water content, OD promotes OS enrichment in certain water-soluble natural components extracted from fruits, such as vitamins and minerals. For this reason, to recycle it for new food formulation seems to be an attractive alternative. In this paper, changes in soluble solids, a_w, pH, electrical conductivity, density, viscosity and colour in osmotic solution used for kiwifruit dehydration in function of the ratio osmotic solution/fruit (20:1, 10:1 and 5:1) and the number of cycles (up to 10) have been studied. Microbiological analysis of OS and fruit compositional changes were also studied. The results show that during OD likewise water interchange between fruit and OS, a flow of mineral salts and sugar from the fruit to the OS, is produced. Nevertheless OS changes associated to the OD of kiwifruit under the conditions of this study allow OS reuse for at least 10 cycles without any problems related to fruit dehydration level, colour fruit changes, or considerable microbiological contamination.     

Bleaching of defatted flaxseed meal to improve its usage as ingredient in food applications

Brown defatted flaxseed meal (FM) was decolourised by dilute hydrogen peroxide (HP). The bleachability was evaluated as function of the FM concentration (2.5%, 5% and 10%), HP concentrations (1%, 2% and 3%), pH (3, 6, 7 and 9), temperature (25, 50 and 75 °C) and reaction time (2, 5 and 10 min). The product whiteness and yellowness were better at pH 9% and 3% HP concentration. The bleachability was enhanced by increasing the temperature but was inversely proportional to the meal concentration. The colour L* value was the highest at 2.5% FM, 3% HP, pH 9 and 10 min at 75 °C (L* = 74.82 ± 0.56) and was the lowest at 10% FM, 1% HP, pH 3 at 25 °C during 10 min (L* = 36.17 ± 0.45). These results may be exploited to improve the profitability of the flax sector using bleached meal as ingredient in food formulations.     

Potato flour as a functional ingredient in bread: evaluation of bread quality and starch characteristics

Potatoes have been added to bread for improvement of texture and moisture retention. The functional quality and starch digestibility in bread containing 5%, 10% or 15% potato flour were evaluated. Farinograph absorption of wheat and potato flour blends ranged from 59.0% to 77.7%. Bread with potato flour had significantly (P < 0.05) lower bread firmness during storage. There was a significant (P < 0.05) decrease in starch molecular weight as the level of potato flour increased. Inclusion of potato flour in these breads significantly (P < 0.05) increased the level of resistant starch (RS), while significantly (P < 0.05) decreasing the estimated glycemic index (eGI). Bread with no potato flour had 5.2% RS and an eGI of 95, while the bread with 15% potato flour had 11.3% RS and an eGI of 87. Overall, the addition of potato flour may reduce dough strength and loaf volume, but it reduced staling and increased resistant starch content of the bread.     

Species identification by SDS-PAGE of red algae used as seafood or a food ingredient

The identification, by SDS-PAGE, of four red algae used as sea vegetables or ingredients by the food industry, was performed. They were Palmaria palmata (Dulse), Chondrus crispus (Pioca), Porphyra umbilicalis (Nori), Gracilaria verrucosa (Ogo-nori). For each species, variations in protein patterns were observed, according to the season. However, for all species, some protein bands were always present during the yearly cycle of the plant. The reference pattern of P. palmata was composed of six protein bands with apparent molecular weights between 59.6 and 15.2 kDa. The G. verrucosa pattern was constituted of eight permanent bands. Two pattern bands, with apparent molecular weights of 49.1 and 45.9 kDa,differentiated the G. verrucosa profile from other seaweed patterns. C. crispus could be identified by a reference pattern composed of seven bands; three, with close molecular weights (49.3; 46.2 and 43.2 kDa), were characteristic of this species. Finally, the P. umbilicalis pattern showed seven bands with molecular weights between 73.1 and 15.9 kDa. The presence of a band with a molecular weight above 70 kDa appeared to be specific to the Porphyra pattern. So the SDS-PAGE seemed able to identify the four red species used by the food industry, but this analytical method appeared to be applicable only to raw material dried in mild conditions.     

Impact of processing on the functionalization of pumpkin pomace as a food texturizing ingredient

In the context of side-stream valorization, this study aimed to gain insight into the functionalization of industrially-generated pumpkin pomace as texturizing ingredient. Given the matrix complexity of pumpkin pomace, composed of crushed peels, seeds and mesocarp, this study focused on the impact of different sample preparation, as well as mechanical processing, on the microstructural and rheological properties of pumpkin pomace suspensions. Pumpkin pomace suspensions (4% w/w) possessed a solid-like behavior, demonstrating the potential for structure build-up. The application of heat during sample preparation (85°C, 30 min) significantly increased the storage modulus of the pumpkin pomace-derived suspensions, which was found to be related to an increased swelling volume of the suspended particles. Moreover, a combination of partial pectin removal and high pressure homogenization at 80 MPa led to improved network structure formation, as obvious from an increased storage modulus. These results are highly useful as scientific basis for exploring the texturizing potential of pumpkin pomace with minimal processing or conventional preparation methods (e.g. by heat treatment).